1. Field of the Invention
Embodiments of the present invention generally relate to the control of fluid flow in a wellbore. More particularly, the invention relates to a flow control apparatus that actuates upon contact with an actuating agent in the wellbore.
2. Description of the Related Art
In hydrocarbon wells, horizontal wellbores are formed at a predetermined depth to effectively reach formations bearing oil or other hydrocarbons in the earth. Typically, a vertical wellbore is formed from the surface of a well and thereafter, using some means of directional drilling like a diverter, the wellbore is extended along a horizontal path. Because the hydrocarbon bearing formations can be hundreds of feet across, these horizontal wellbores are sometimes equipped with long sections of screened tubing. Generally, the screened tubing consists of tubing having apertures therethough and covered with screened walls, leaving the interior of the tubing open to the inflow of filtered oil.
Horizontal wellbores are often formed to intersect narrow oil bearing formations that might have water and gas bearing formations nearby. Even with exact drilling techniques, the migration of gas and water towards the oil formation and the wellbore is inevitable due to pressure drops caused by the collection and travel of fluid in the wellbore. Typically, operators do not want to collect gas or water along with oil from the same horizontal wellbore. The gas and water must be separated at the surface and once the flow of gas begins it typically increases to a point where further production of oil is not cost effective. Devices have been developed that control the flow of fluid in a horizontal wellbore. Generally, these devices are configured to allow oil to flow through the device but upon indication of water, the device actuates to block the flow of water through the device. One such device is a flow control system that includes a tubular having a plurality of production nozzles. The flow control system further includes a plurality of balls which float in water to seal off the plurality of production nozzles when water is present in the formation fluid. Even though the flow control system is capable of controlling the flow of fluid in the horizontal wellbore, the flow control system may not effectively operate when the formation fluid comprises a mixture of fluid. Additionally, the flow control system can be expensive to manufacture.
There is a need therefore for a cost effective flow control device that effectively operates to limit the inflow of gas or water into the production tubing from the surrounding wellbore formations.